During excavation at Glastonbury Abbey in 1191, an ancient leaden cross is unearthed. It is inscribed with the words hic iacet sepultus inclitus rex arturius—here lies buried the renowned King Arthur—and beneath it are two skeletons. Could these really be the remains of the legendary king and his queen Guinevere? While the monks debate the implications of this discovery, the bones are spirited away by the mysterious Guardians, who are sworn to protect Arthur's remains until, as prophesied, he can return to protect his country in its direst hour. In these five linked mysteries by the Medieval Murderers—historical mystery writers Michael Jecks, Susanna Gregory, Bernard Knight, Ian Morson, and Philip Gooden—the secret of the bones inspires treachery, theft, blackmail, and murder.